Print codes used
These are found in the lower left corner of each sheet, in a month.year style, 3.14 being March 1914. Only the last code is listed here.

Cover codes
The earliest are white waxy covers with the area title in large letters (code WL), or including a diagram of the map area (code WD). Later covers have a decorative crest design by Ellis Martin, originally issued as a black design on buff, with red sheet name (code EB), this was soon replaced by the same design in brown, with a red sheet name and a red border (code ER). Cover details are sometimes printed directly on to the folded map (code DP). Some maps are found in covers supplied by Ordnance Survey agents, and usually have details of the agent on the front (code AG).